@misc{indiciae52301edc98db,
  title = {The vertical gradient of gravity in vertical and near vertical boreholes},
  author = {Larry A. Beyer},
  year = {1971},
  doi = {10.3133/ofr7142},
  url = {https://pubs.usgs.gov/publication/ofr7142},
  note = {Source identifier: ofr7142}
}